Highlights

Describe the levels of PM2.5, PM10 and TSP at urban, rural and industrial sites.Simulate the atmospheric PCDD/F concentration for urban, rural and industrial site.Present simulated monthly dry, wet and total deposition fluxes of PCDD/Fs.Evaluate the dry deposition velocities of PCDD/Fs.Evaluate the rainfall concentration and scavenging ratios of PCDD/Fs.

Abstract

Kaohsiung County, in southern Taiwan, has both highly industrial and rural areas. In this study, the characteristics of PCDD/Fs in the ambient air of Kaohsiung (urban), Meinong (rural) and Xiaogang (heavy industrial zone) in 2014 and 2015 were modeled based on the prevailing meteorological conditions and the measured ambient air concentrations of PM2.5, PM10 and TSP. The yearly average PM2.5 concentrations in the ambient air of the three areas were in the range of 23 to 31 µg m–3, all above the National Air Quality Standard of Taiwan (15 µg m–3). The simulated average concentrations of PCDD/Fs in the whole of Kaohsiung area in terms of toxicity equivalent were in the range of 0.034–0.053 pg WHO2005-TEQ m–3. The average total deposition fluxes of total-PCDD/Fs-WHO2005-TEQ ranged between 155.4 and 276.6 pg WHO2005-TEQ m–2 month–1 with 1,2,3,7,8-PeCCD and 2,3,4,7,8-PeCDF being the dominant congeners in terms of PCDD/Fs WHO2005-TEQ. Xiaogang area with highly industrial activities had the highest concentrations of PM2.5 and PCDD/Fs and corresponding total-PCDD/Fs WHO2005-TEQ deposition fluxes, while the Meinong in the rural site recorded the lowest. Average dry deposition velocities of total PCDD/Fs WHO2005-TEQ for both 2014 and 2015 were 0.162, 0.148 and 0.161 cm s–1 for Kaohsiung, Meinong and Xiaogang, respectively, while the average scavenging ratios of total PCDD/Fs WHO2005-TEQ were 6232, 4701 and 6802, for Kaohsiung, Meinong and Xiaogang, respectively. The information provided in this work is useful for both further studies and environmental control strategies concerning atmospheric aerosols and dioxins.